1. Field of the Invention
The present invention pertains to a downhole shut-in control valve which is automatically actuated at a predetermined time for performing certain wellbore tests and other operations requiring timed shut-in of well fluid flow.
2. Background
In certain wellbore tests, such as pressure transient testing of formation characteristics and well fluid flow, it is desirable to use a downhole shut in device to shut off well fluid flow to minimize the effects of wellbore storage and afterflow which are generally caused by compressive and/or thermal energy or by a changing liquid level in the well tubing. The shut in device should also be capable of operating at a predetermined time to carry out the test procedure and without interruption of fluid flow prior to the initiation of the test. Conventional wellbore shut-in valve devices require wireline or slickline connection to the valve itself to run the device and set it and then to perform the valve closure operation. In many instances, a separate trip into the wellbore is required to effect setting or operation of the valve which can disrupt wellbore fluid flow and pressure thereby delaying the wellbore test or producing false test readings.
Accordingly, it is desirable to be able to provide a wellbore shut-in valve which will operate at a predetermined time without interruption of other wellbore operations upon placement of the valve in a predetermined location in a fluid-conducting tubing string. Such a valve may also be used to isolate flow from commingled streams which are separated by a locking nipple. The present invention provides an improved wellbore shut-in tool or flow control valve having the desired features and providing for the improved test operations mentioned above.